Russia’s average daily oil refining rate fell to the lowest weekly level in ten months after a flurry of Ukrainian drone attacks hit several major facilities.Refiners processed 5.03 million barrels a day of crude from March 14 to 20, according to a person with knowledge of industry data. That’s down more than 400,000 barrels a day from the average for the first 13 days of the month, according to Bloomberg calculations based on historical data. With Russia’s invasion of Ukraine in its third year, Kyiv is using drones to target its enemy’s key industry, seeking to curb fuel supplies to the front line and cut the flow of petrodollars into Kremlin coffers. The attacks this year have targeted 13 major refineries and two smaller plants, taking offline between 480,000 and 900,000 barrels a day of processing capacity, according to a Bloomberg survey.